bullethawk

I bought a new master cylinder and when I went to prime it the oil started coming out of the holes. As far as I remember no oil came out of the cylinder. Does anyone know if this is normal?

ezone

Oil? I hope you mean brake fluid.
Petroleum oil should never be near brake components.
What holes?

bullethawk

brake fluid, and the holes where the brake lines go

ezone

Ok...



When you fill the reservoir, fluid is free to come out of the brake line ports. Normal.

Remember to Bench Bleed the new master before installation.

bullethawk

that's what I forgot to do. been a long time sense I did one of these. anyway I installed it before priming it. So I bleed it on the car. got some air, did all the wheels got nice clean fluid in whole system. still no brake pedal. also loosened the lines at the proportionng valve still no pedal. ordered another used valve should be in this week. nothing left in the braking system so that should work. thanks for your help.

ezone

Take the new master cylinder off the car and bench bleed it.

bullethawk

I took the master cylinder out and filled it with brake fluid using a vacuume pump. Installed it and still pedal goes to the floor.

ezone

Was the master actually bad, or is there another reason the pedal would go to the floor?

All 4 bleeder screws are free and working? None broke off?


General info:

How to bench bleed a master cylinder:
http://autorepair.about.com/od/fixityourself/ss/MC_bench-bleed.htm


After bleeding and reinstallation, you still need to bleed out the rest of the system.

Sometimes it needs more help than just that.....

If there is so much air trapped in the system that it's impossible to bleed, I pick a wheel and use the method in the last paragraph of page #4 in the linked article above:

you'll cover the holes tightly with your fingers when you release the cylinder. Keep pumping until there are no more bubbles



Pick a wheel....I'd start in the right rear.....

Open the bleeder and cover with a finger (rubber gloves help here)
while someone else pumps the pedal (your finger is now a check valve, this is much quicker than using a wrench on the bleeder)
until there is good fluid flow,
then close the bleeder and move to the next wheel.
Repeat until all 4 have flow and pedal feel is somewhat restored.
Then you may still need to bleed normally with a wrench.